I tried doing the heat transfer with the Oster dry iron and SuperSoft heat transfer paper on a cotton T-shirt. When I put a lot of pressure on the heat transfer with the iron, lines from the edges of the sole plate appeared on the T-shirt image. For my next attempt, I placed parchment paper over the heat transfer. That technique decreased the appearance of lines. You can see two horizontal lines crossing the lizard's tail. For my third attempt., I used the parchment paper again but decreased the pressure with the iron on the heat transfer. This time, there were no lines.
Diana Carol Clarke